INIT: Entering runlevel: 2 [[36minfo[39;49m] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added 'ci-upstream-next-kasan-gce-4,10.128.15.205' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 56.567082] refcount_t: underflow; use-after-free. [ 56.572144] ------------[ cut here ]------------ [ 56.577148] WARNING: CPU: 0 PID: 3005 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 56.585814] Kernel panic - not syncing: panic_on_warn set ... [ 56.585814] [ 56.593151] CPU: 0 PID: 3005 Comm: syzkaller404557 Not tainted 4.14.0-rc5-next-20171018+ #36 [ 56.601703] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 56.611025] Call Trace: [ 56.613589] dump_stack+0x194/0x257 [ 56.617188] ? arch_local_irq_restore+0x53/0x53 [ 56.621830] ? vsnprintf+0x1ed/0x1900 [ 56.625608] panic+0x1e4/0x41c [ 56.628779] ? refcount_error_report+0x214/0x214 [ 56.633509] ? show_regs_print_info+0x65/0x65 [ 56.637981] ? __warn+0x1a9/0x1e0 [ 56.641409] ? refcount_sub_and_test+0x167/0x1b0 [ 56.646134] __warn+0x1c4/0x1e0 [ 56.649385] ? refcount_sub_and_test+0x167/0x1b0 [ 56.654121] report_bug+0x211/0x2d0 [ 56.657725] fixup_bug+0x40/0x90 [ 56.661068] do_trap+0x260/0x390 [ 56.664422] do_error_trap+0x120/0x390 [ 56.668277] ? vprintk_emit+0x49b/0x590 [ 56.672227] ? do_trap+0x390/0x390 [ 56.675738] ? refcount_sub_and_test+0x167/0x1b0 [ 56.680471] ? vprintk_emit+0x3ea/0x590 [ 56.684433] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 56.689249] do_invalid_op+0x1b/0x20 [ 56.693024] invalid_op+0x18/0x20 [ 56.696446] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 56.701776] RSP: 0018:ffff8801d23269c8 EFLAGS: 00010282 [ 56.707106] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 56.714345] RDX: 0000000000000026 RSI: 1ffff1003a464cf9 RDI: ffffed003a464d2d [ 56.721588] RBP: ffff8801d2326a58 R08: 0000000000000001 R09: 0000000000000000 [ 56.728829] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a464d3a [ 56.736068] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d37642bc [ 56.743331] ? refcount_sub_and_test+0x167/0x1b0 [ 56.748058] ? refcount_inc+0x50/0x50 [ 56.751827] ? sctp_outq_free+0x15/0x20 [ 56.755772] ? sctp_do_sm+0x271b/0x6a30 [ 56.759716] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 56.764437] ? sctp_close+0x3c6/0x980 [ 56.768203] ? inet_release+0xed/0x1c0 [ 56.772062] ? sock_release+0x8d/0x1e0 [ 56.775924] sctp_wfree+0x183/0x620 [ 56.779521] ? __sctp_write_space+0x910/0x910 [ 56.784076] skb_release_head_state+0x124/0x200 [ 56.788719] skb_release_all+0x15/0x60 [ 56.792578] consume_skb+0x153/0x490 [ 56.796259] ? sctp_chunk_put+0x99/0x420 [ 56.800298] ? alloc_skb_with_frags+0x750/0x750 [ 56.804936] ? sctp_chunk_hold+0x20/0x20 [ 56.808970] ? refcount_sub_and_test+0x115/0x1b0 [ 56.813697] ? refcount_inc+0x50/0x50 [ 56.817465] ? mark_held_locks+0xaf/0x100 [ 56.821585] ? sctp_datamsg_put+0x456/0x560 [ 56.825889] sctp_chunk_put+0x29c/0x420 [ 56.829837] ? sctp_chunk_hold+0x20/0x20 [ 56.833870] ? sctp_transport_dst_confirm+0x50/0x50 [ 56.838870] ? sctp_sched_fcfs_dequeue+0x198/0x290 [ 56.843776] ? sctp_sched_dequeue_common+0x5d0/0x5d0 [ 56.848861] sctp_chunk_free+0x53/0x60 [ 56.852722] __sctp_outq_teardown+0xa5b/0x1230 [ 56.857279] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 56.862182] ? __kernel_text_address+0xd/0x40 [ 56.866660] ? unwind_get_return_address+0x61/0xa0 [ 56.871562] ? __save_stack_trace+0x7e/0xd0 [ 56.875857] ? add_lock_to_list.isra.32+0x292/0x39b [ 56.880851] ? check_noncircular+0x20/0x20 [ 56.885057] ? print_irqtrace_events+0x270/0x270 [ 56.889794] ? lock_acquire+0x1d5/0x580 [ 56.893738] ? lock_acquire+0x1d5/0x580 [ 56.897691] ? lock_timer_base+0x1a3/0x2b0 [ 56.901901] ? find_held_lock+0x35/0x1d0 [ 56.905941] ? sock_def_wakeup+0x1f9/0x350 [ 56.910142] ? lock_downgrade+0x990/0x990 [ 56.914262] ? lock_release+0xa40/0xa40 [ 56.918211] sctp_outq_free+0x15/0x20 [ 56.921985] sctp_association_free+0x2d0/0x930 [ 56.926639] ? sctp_asconf_queue_teardown+0x700/0x700 [ 56.931801] ? sock_def_wakeup+0x222/0x350 [ 56.936179] ? sk_dst_check+0x560/0x560 [ 56.940134] ? sctp_association_put+0x74/0x2f0 [ 56.944694] ? sctp_association_hold+0x20/0x20 [ 56.949245] ? __lock_is_held+0xb6/0x140 [ 56.953283] sctp_do_sm+0x271b/0x6a30 [ 56.957066] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 56.963095] ? print_irqtrace_events+0x270/0x270 [ 56.967818] ? __lock_acquire+0x6aa/0x3d50 [ 56.972023] ? print_irqtrace_events+0x270/0x270 [ 56.976763] ? mark_held_locks+0xaf/0x100 [ 56.980883] ? retint_kernel+0x10/0x10 [ 56.984740] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 56.989729] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 56.994465] ? retint_kernel+0x10/0x10 [ 56.998343] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 57.002902] sctp_close+0x3c6/0x980 [ 57.006508] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 57.011752] ? __lock_acquire+0x6aa/0x3d50 [ 57.015958] ? check_noncircular+0x20/0x20 [ 57.020166] ? __lock_acquire+0x6aa/0x3d50 [ 57.024372] ? check_noncircular+0x20/0x20 [ 57.028580] ? locks_remove_file+0x3fa/0x5a0 [ 57.032963] ? fcntl_setlk+0x10c0/0x10c0 [ 57.037000] ? __fsnotify_parent+0xb4/0x3a0 [ 57.041294] ? ip_mc_drop_socket+0x1ce/0x230 [ 57.045680] inet_release+0xed/0x1c0 [ 57.049377] sock_release+0x8d/0x1e0 [ 57.053150] ? sock_release+0x1e0/0x1e0 [ 57.057093] sock_close+0x16/0x20 [ 57.060516] __fput+0x327/0x7e0 [ 57.063944] ? fput+0x140/0x140 [ 57.067223] ? _raw_spin_unlock_irq+0x27/0x70 [ 57.071708] ____fput+0x15/0x20 [ 57.074970] task_work_run+0x199/0x270 [ 57.078863] ? task_work_cancel+0x210/0x210 [ 57.083162] ? __do_page_fault+0x3d6/0xd60 [ 57.087375] get_signal+0x1343/0x16d0 [ 57.091160] ? mm_fault_error+0x2c0/0x2c0 [ 57.095280] ? ptrace_notify+0x130/0x130 [ 57.099322] ? check_noncircular+0x20/0x20 [ 57.103527] ? __do_page_fault+0xd60/0xd60 [ 57.107729] ? do_page_fault+0xee/0x720 [ 57.111673] ? __do_page_fault+0xd60/0xd60 [ 57.115883] ? check_noncircular+0x20/0x20 [ 57.120086] ? find_held_lock+0x35/0x1d0 [ 57.124121] ? retint_kernel+0x10/0x10 [ 57.127989] do_signal+0x94/0x1ee0 [ 57.131503] ? put_unused_fd+0x62/0x70 [ 57.135359] ? lock_downgrade+0x990/0x990 [ 57.139476] ? setup_sigcontext+0x7d0/0x7d0 [ 57.143776] ? do_raw_spin_trylock+0x190/0x190 [ 57.148342] ? __put_unused_fd+0x183/0x250 [ 57.152559] ? alloc_fdtable+0x280/0x280 [ 57.156587] ? cpumask_weight.constprop.1+0x48/0x48 [ 57.161575] ? _copy_to_user+0xa2/0xc0 [ 57.165445] ? _raw_spin_unlock+0x22/0x30 [ 57.169567] ? fput+0xd2/0x140 [ 57.172730] ? SYSC_accept4+0x4ec/0x850 [ 57.176688] ? exit_to_usermode_loop+0x8c/0x310 [ 57.181340] exit_to_usermode_loop+0x214/0x310 [ 57.185894] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 57.191400] ? _raw_spin_unlock_irq+0x27/0x70 [ 57.195866] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 57.200856] syscall_return_slowpath+0x42f/0x510 [ 57.205591] ? finish_task_switch+0x1aa/0x740 [ 57.210057] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 57.215058] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 57.219971] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 57.224956] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 57.229688] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 57.234409] RIP: 0033:0x446539 [ 57.237575] RSP: 002b:00007f4cdf284dc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000120 [ 57.245425] RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000446539 [ 57.252662] RDX: 0000000020137ffc RSI: 0000000020b53ff0 RDI: 0000000000000003 [ 57.259899] RBP: 0000000000000000 R08: 00007f4cdf285700 R09: 00007f4cdf285700 [ 57.267137] R10: 0000000000080000 R11: 0000000000000202 R12: 0000000000000000 [ 57.274419] R13: 00000000007efe7f R14: 00007f4cdf2859c0 R15: 0000000000000000 [ 57.282233] Dumping ftrace buffer: [ 57.285824] (ftrace buffer empty) [ 57.289510] Kernel Offset: disabled [ 57.293111] Rebooting in 86400 seconds..